US2057218A

US2057218A - Method and apparatus for producting fire extinguishing foam

Info

Publication number: US2057218A
Authority: US
Inventors: Lewis G Morris
Original assignee: PYRENE MINIMAX CORP
Current assignee: PYRENE MINIMAX CORP; PYRENE-MINIMAX Corp
Priority date: 1934-08-30
Filing date: 1934-08-30
Publication date: 1936-10-13
Anticipated expiration: 1953-10-13

Description

L. G. M. TIMPSON 2,057,218

EXTINGUIS-HING FOAM METHOD AND APPARATUS FOR PRODUCDIG FIRE Fil ed Aug. 50, 1954 Patented Oct. l, 1936 V PATENT OFFICE METHOD AND APPARATUS FOR PRODUC- ING FIRE EXTINGUISHING FOAM Lewis G. Morris Timpson, Plainlield, N. a, as-

signor to Pyrene-Minimax Corporation, a corporation of Delaware Application August 30,

13 Claims.

This invention relates to foam-forming methods and apparatus, and particularly to methods and apparatus for generating a stream of foam consisting of relatively stable bubbles, for blanketing fires capable of such treatment, and

extinguishing them principally by excluding oxygen from the seat of the blaze. Heretofore it has been common for this purpose to utilize foamforming chemicals, which react to form a gas .10 that is then incorporated in a stream of water with some suitable stabilizing agent to make foam. According to the present invention, however, a very satisfactory foam may be produced by the use of only water, air and a stabilizing agent, al-

though another suitable gas may be substituted in whole or in part for air if desired.

Prior attempts have been made to produce what may be termed air-foam, by the incorporation of air in watercontaining saponin or a similar stabilizing agent, but these have not proved altogether successful for fire extinguishing purposes due to the difliculty of supplying an adequate quantity of air to a stream of water. It has been found that in attempting to draw air into a flowing stream of water by the movement of the stream, as it passes through a jet for example, not more than about half enough air is drawn into a stream of sufficient size for fire extinguishing purposes to produce satisfactoryffoam. Thus a stream of water discharged through a jet orifice of a given diameter will present an outer surface, having an area per lineal inch that is a function of the diameter of the stream. The

quantity of air that can be entrained in such a stream is necessarily limited by this surface area. To visualize this we may consider a flowing stream as having 'a large number of indentations in its surface and each of these indentations may be considered to form a pocket to receive air, much as the buckets of an endless conveyor receive their charge of material in passing a loading point. Now the stream having the surface area men-. tioned will have a certain volume or cubical capacity per inch of length that is dependent upon 6 the square of the diameter. The ratio between this volume andthe-surface area specified determines the ratio of air to water that will exist in the pipe beyond the point at which air is sucked into the stream.

0 As stated, this ratio for a jet of suitable diameter for fire extinguishing purposes, say /2 inch,

is such as to produce a very poor grade of foam due to the presence of only about half the required amount of air or gas. If the size of the jet :5 is increased the ratio of air to water is even 1934, Serial No. 742,041 (01. 261-76) worse. If the jet is decreased in diameter the ratio of air to water will be improved, but the resulting stream of foam will be too small to be effective for fire extinguishing purposes and the frictional losses in attempting to flow a small 5 stream through a pipe or hose will be excessive.

The present invention has for its primary object the production of a stable, durable fire extinguishing foam of large volume in relation to the water used, by the intermingling of'appro- 10 priate proportions of air or similar gas, water and a stabilizing agent. Toward this end the invention contemplates so increasing the surface area of a flowing stream of water as to insure entrainment of a suificient amount of air to produce a 5 most satisfactory foam in appropriate quantity to be effective for fire extinguishing purposes. This may be very effectively accomplished by dividing a stream of water of suitable volume into a plurality of smaller streams, passing each of these 20 separately through a jet arranged to admit air and then merging the streams of water and air into a single stream for ultimate distribution. Saponin or other foam stabilizing agent may be introduced in any convenient way, either in advance of the jets or at one or more of the jets.

Other features, objects and advantages will appear from a description of the invention, together with the accompanying drawing, in which:

Fig. 1 is a vertical section of an apparatus operso able in accordance with the present invention; and

Fig. 2 is a transverse section on line 2-2 of Fig. 1.

Before entering upon a description of the par-- ticular apparatus preferred for the conduct of my process the principles upon which it is construct-' ed may be more readily appreciated from the following considerations: It may be assumed that a sufficient volume of water for the production of 40 fire extinguishing foam will be supplied by a solid stream of 14 mm. diameter. The flow area of such a stream is approximately 153.9 sq. mm., and the unit surface area will be pi times the diameter or approximately 44 sq. mm. per linear 45 mm. If-we divide such a stream into six equal cylindrical streams, the flow area of each will be 25.65 sq. mm., which means that the diameter of each must be 5.71 mm. In other words, at a given velocity of flow, six streams of water 5.71 mm. in diameter will deliver thesame volume of water per unit time as one stream of 14 mm. diameter.

. The unit surface area of each is equal to pi times the diameter or small stream approximate- 1y 17.94 sq. mm. per linear mm. The combined unit surface area of all six streams will then be 107.64 sq. mm., or nearly two and one-half times that of the solid 14 mm. stream. Since one of the six streams is not exposed to the air, the unit surface area available for entraining air is 89.7 sq. mm., slightly more than twice the unit surface area of the solid 14 mm. stream. It is thus apparent that by the use of the present invention it is possible to entrain a much greater volume of air in a given volume of water, and thus produce a greater quantity of foam and one having better body.

It should be noted that the above dimensions are not in any way critical, and a larger or smaller number of streams, or streams of varying dimensions, may be used. Likewise it is not necessary to use cylindrical streams, which are specified herein merely for purposes of illustration.

The apparatus illustrated in the drawing is suitable for carrying out the present invention, Referring, to Fig. 1, water from any suitable source, and under suitable pressure, is brought into a jet chamber indicated at H. The chamber In is defined by a bell member l2 and a jet disc l3, threaded into the mouth of the member 12. A plurality of air ejector nozzles M are suitably secured in apertures extending through present instance five nozzles M are arranged in a symmetrical manner around the center of the disc as illustrated in Fig. 2. Other arrangements may be employed if desired. In addition to the nozzles- H, a nozzle l5, for use in introducing a stabilizing agent into the stream, and which for convenience will be called a soap ejector nozzle, is similarly secured centrally of the jet disc IS. A packing gland I50 is preferably provided around each of the nozzles 14 and I5 and any suitable means may be employed for preventing leakage between the bell l2 and disc l3.

Opposite each of the nozzles a. short distance therefrom, is a receiver together with its associated nozzle M an ejector for the entrainment of the receivers iii are preferably provided with passages having a constricted portion between flaring portions at the two ends. The receivers l6 are secured in suitable apertures of a receiver disc 11, which is supported in the mouth of a bell member I8. The receiver disc I! and bell member 18 define a receiver chamber I9. Spacer rods 20 connect the jet disc l3 and receiver disc 11, and maintain the nozzles l4 and receivers IS in proper relationship. If desired the space between the ends of the bells l2 and I8 may be partially enclosed in any suitable way so long as provision is made for the ready access of air or other gas around the receivers IS.

A receiver 2|, arranged centrally of the receiver disc I? in direct line with the nozzle l5, differs from the receivers IS in that it is provided vith an enlarged bell end 22, which is adapted to seat within an annular flange 23 formed upon the face of the jet disc l3, thus sealing to the air the ejector formed by the nozzle 15 and receiver ii. A conduit 23 is tapped into the bell end 22 of receiver 2!, and is connected to a suitable supply of saponin or other foam-stabilizing agen In the operation of the apparatus described, .water under suitable pressure is introduced through the conduit H into the jet chamber l8, from which it issues in six separate jets through the nozzles I4 and i5. As the jets from nozzles H, but spaced I 6, which comprises l through a supply conduit the jet disc iii. In the l4 pass into their respective receivers l6 they entrain in their exposed surfaces a quantity of air, or such other gas as surrounds the apparatus. The jet from the nozzle l entrains and takes up a quantity of saponin or other foamstabilizing agent which is supplied through conduit 23, and all of the jets are again merged in the receiver chamber l9. As the stream thus formed flows out through a discharge conduit 24, the gas and stabilizing agent are distributed throughout the stream, forming a stable foam. It is apparent that the volume of foam thus formed is greater than would be possible by the use of a single solid jet of water and the absence of excess water lends better body and durability to the foam produced.

While the form of apparatus described in detail is considered the preferred construction it will be appreciated that various changes may be made. For example, the foam stabilizing jet might be arranged in advance of and in series with the group of air jets instead of in parallel therewith or the stabilizer might be added by means of a force pump on either the high or low side of one or more of the air jets. Furthermore the separate receivers for the jets might be replaced by a single large receiver.

The terms and expressions employed herein are used for purposes of description and not of limitation. It is recognized that many modifications of the construction disclosed may be made within the scope of the present invention as defined by the claims which follow.

What is claimed is:-

1. In apparatus for producing fire extinguishing foam, a plurality of ejectors, means for passing a stream of water through each of said ejectors, means for introducing a foam-stabilizing agent into one of said streams, means for introducing a gas into the remaining of said streams by aspiration, and means for merging said streams in a single discharge conduit.

'2. In apparatus for producing fire extinguishing foam, a jet chamber, means for supplying water to said jet chamber, a plurality of nozzles piercing a wall of said jet chamber, a receiver chamber, a plurality of receivers piercing a wall of said receiver chamber and extending toward said nozzles, each of said receivers registering with one of said nozzles, means for introducing foam stabilizing material into said r :ceiver chamber and a discharge conduit leading from said receiver chamber.

3. In apparatus for producing rlre extinguishing foam, a jet chamber, means for supplying water to said jet chamber, a plurality of nozzles piercing a wall of said jet chamber, a receiver chamber, a plurality of receivers piercing a wall of said receiver chamber and extending toward. said nozzles, each of said receivers registering with one of said nozzles, means for supplying a foam stabilizing agent to one of said receivers, means for supplying a gas to a plurality of said receivers, and a discharge conduit leading from said receiver chamber.

4. In apparatus for producing fire extinguishing foam, a jet chamber, means for supplying water to said jet chamber, a plurality of nozzles piercing a wall of said jet chamber, a receiver chamber, a plurality of receivers piercing a wall of said receiver chamber and extending toward said nozzles, each of said receivers registering with one of said nozzles, means for supplying a foam stabilizing agent tov one of said receivers, the remaining receivers being in open communication with the atmosphere, and a discharge conduit leading from said receiver chamber.

5. In apparatus for producing fire extinguishing foam, means for supplying a stream 01' water, means for dividing said supply stream into a plurality of secondary streams, means for introducing a foam-stabilizing agent into one of said secondary streams, means for introducing a gas into others of said secondary streams by aspiration, and means for merging said secondary streams to form a. single discharge stream.

6. In apparatus for producing fire extinguishing foam, means for supplying a. stream of water, means for dividing said supply stream into a plurality of secondarystreams, means for supplying a gas under substantially atmospheric pressure to the outer surfaces of a number of said secondary streams, means for merging said secondary streams to form a single discharge stream, and means for aspirating a foam stabilizing agent into one of said streams.

7. In apparatus for producing fire extinguishing foam a plurality of receivers, means for passing a stream of water through each of said receivers, a plurality of said ejectors being arranged to entrain a gas in the outer surfaces of said streams by aspiration, means for merging the streams from all of said receivers into a single stream, and means for supplying a foam stabilizing agent into the water in one of said streams.

8. A method of forming fire extinguishing foam which comprises splitting a flowing stream of water into a plurality of separately confined smaller streams, introducing a gas into a number of said streams by aspiration, merging said smaller streams into a single stream, and adding a foam stabilizing agent to said merged stream.

9. A method of forming fire extinguishing foam which comprises splitting a flowing stream of water into a plurality of separately confined smaller streams. introducing a gas into a number of said streams by the action 01' the flow thereof, merging said smaller streams into a single stream, and adding a foam stabilizing agent to one of said streams.

10. A method of forming fire extinguishing foam which comprises splitting a flowing stream 01' water into a plurality of smaller streams, entraining a gas in the outer surfaces of a number 01' said streams by aspiration, merging said smaller streams into a, single stream, and adding a foam stabilizing agent to one of said smaller streams.

11. The method of forming fire extinguishing foam comprising dividing a stream of water into a plurality of smaller streams, aspirating air independently into a number of said smaller streams, introducing foam stabilizing ingredients into another of said streams, and finally merg- "ing all of said smaller streams into a single large stream.

12. In apparatus for producing fire extinguishing foam, a plurality of receivers exposed to the atmosphere, a plurality of nozzles, means for passing a stream of water through each of said nozzles into said receivers, means for merging the resulting streams in a single discharge conduit. and means for introducing a foam stabilizing agent into said merged stream.

13. In apparatus for producing fire extinguishing foam, a plurality of receivers exposed to the atmosphere, a. receiver sealed off from the atmos phere, means for passing a stream of water through a separate nozzle into each of said receivers, means for introducing a foam-stabilizing agent into said sealed receiver, and means for merging the resulting streams in a single dis charge conduit.

LEwIsG. MORRIS 'rmpson.